[1] ICO, Dept Med Phys & Radiat Safety, Barcelona, Spain
[2] Univ Hosp Coventry, Arden Canc Ctr, Dept Clin Oncol, Coventry, W Midlands, England
[3] Clatterbridge Ctr Oncol, Dept Clin Oncol, Bebington, Merseyside, England
[4] Clatterbridge Ctr Oncol, Bebington, Merseyside, England